Widely known processes for producing cyclic N-hydroxyimide compounds are processes of allowing a cyclic acid anhydride to react with hydroxylamine. Japanese Unexamined Patent Application Publication No. 2001-233854 discloses a process of producing a cyclic N-hydroxyimide compound by allowing a cyclic acid anhydride to react with hydroxylamine in a carboxylic acid solvent. This process, however, cannot be said to be industrially satisfactory, since the yield of the cyclic N-hydroxyimide compound on the basis of the cyclic acid anhydride is as low as 60% to 70%. Japanese Patent No. 3288682 discloses a process of producing a cyclic N-hydroxyimide compound by allowing a cyclic acid anhydride to react with a hydroxylamine salt in a solvent without adding abase. The yield of the cyclic N-hydroxyimide compound according to this process significantly varies from 40% to 90%, and a higher yield is achieved when the hydroxylamine salt is used in an amount of about two times by mole that of the cyclic acid anhydride.
As is described above, the conventional processes of producing a cyclic N-hydroxyimide compound by the reaction between a cyclic acid anhydride and hydroxylamine show low yields of the cyclic N-hydroxyimide compound on the bases of the cyclic acid anhydride and offer low utilization rates of the cyclic acid anhydride. A possible solution to improve this is recovery and reuse of unreacted cyclic acid anhydride, but this invites extra cost typically for facilities for recovery and is economically disadvantageous. The yield of the cyclic N-hydroxyimide compound is increased by using an excess amount of hydroxylamine to the cyclic acid anhydride, but this invites a decreased utilization rate of hydroxylamine and is also economically disadvantageous.
Most processes for producing cyclic N-hydroxyimide compounds described in documents use a cyclic acid anhydride, but few employ a dicarboxylic acid, as a raw material component to be reacted with hydroxylamine or a salt thereof. Consequently, it is substantially impossible to yield a cyclic N-hydroxyimide compound from a dicarboxylic acid which is resistant to conversion into a cyclic acid anhydride. Even in the case of a dicarboxylic acid being readily converted into a cyclic acid anhydride, demands have been made to provide a process of producing a cyclic N-hydroxyimide compound directly from the dicarboxylic acid, bypassing a cyclic acid anhydride. This process avoids the step of converting the dicarboxylic acid into a cyclic acid anhydride and is economically very advantageous typically in plant cost.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2001-233854
Patent Document 2: Japanese Patent No. 3288682